About five years ago, I was diagnosed with schizophrenia. Fortunately,
medication works well to manage the illness. Occasionally, I experience
a flare-up of symptoms, but my wife and I are very good about detecting
the early warning signs. Please explain, without too many technical terms,
the structural differences between the brains of persons with schizophrenia
and those without the illness.

Of all the methods used to investigate biological abnormalities in psychiatric
illnesses, structural neuroimaging studies such as CAT (computed axial
tomography) and MRI (magnetic resonance imaging) measurements have provided
some of the most consistent evidence for brain abnormalities in people
with schizophrenia. However, these studies show subtle rather than dramatic
changes, and the findings are not seen in all cases of schizophrenia,
so they are not useful as clinical tests for making the diagnosis of the
disorder.
The first report by Eve Johnstone and Tim Crow from England in 1976, using
CAT scans, showed enlargement in the brains in schizophrenic patients
of the fluid-filled spaces normally found in the brain.

The entire cortex (gray matter) of the brain in schizophrenia is, on
average, smaller in volume by only about 5 percent than in healthy people
without the disorder. However, this loss is not equally distributed in
all brain regions. Recent MRI methods generally show specific deficits
in gray matter volumes of around 20 percent in frontal and temporal regions
of the brain. Such studies suggest the most notable brain changes in schizophrenia
occur in a very organized and interconnected brain system that includes
areas that normally help us to process speech and language, make complicated
decisions and learn rules.

These regions are most developed in humans, (which may explain why schizophrenia
only occurs in humans) and they may be especially vulnerable to disruptions
in nerve cell function or in making connections during brain development
in the fetus. These areas mature more slowly than other brain regions.
Therefore, a process occurring during a particular brain development
phase might affect these regions but spare others. Secondly, th e development
of these brain regions is lengthy, extending into early adult life. These
frontal and temporal lobe regions only fully "come on line"
in late adolescence, (which may explain why schizophrenia typically begins
during this period of life).

The normal brain is asymmetrical; some regions are larger on the left
or right side. These asymmetries appear disturbed in schizophrenia. For
example, some research has found a reversal of the normal left-right relationship
of temporal lobe speech areas in the brain. This abnormality seems to
be connected with the tendency of people with schizophrenia to "hear
voices" and to show speech disturbances when acutely ill. There is
also evidence for disturbed connections between different brain regions
in schizophrenia.

However, the cause and mechanism of all of these brain abnormalities
remains unknown. Ongoing advances in structural neuroimaging technology
promise that more fine-tuned approaches for investigating the brain in
schizophrenia become available, allowing researchers to match up the anatomical
findings with clinical, cognitive, postmortem, functional neuroimaging
and EEG (electro encephalogram) data.